UPDATE: Sony has released an image taken with its curved sensor, and provided a couple more details on what we might expect from its curved sensor technology. Our original story can still be found below.

Nikkei reports that Sony has released an image taken with its new curved sensor technology, which you'll see below.

First released image taken with Sony's curved sensor technology. [Source:Nikkei]

While a high-resolution version was not provided, some may view this image as being 'historic', and others will appreciate the simple fact that Sony's curved sensor technology is not simply a concept in its early stages of development.

Of further interest are comments made by Sony indicating that - in the interest of an early practical appication - the first prototype may not have the 24 million pixel resolution one might expect from an RX1 follow-up (admittedly, we are relying on Google translation here, so do give us some room for error). Furthermore, comments from Sony indicate that it's difficult to design a zoom lens of 'high power' that works with the curved sensor. This comes as no surprise. Indeed, we mentioned earlier that field curvature changes with focal length of the lens (as well as other factors), and so one particular curvature can really only be ideally suited to one particular focal length.

So - to begin with anyway - Sony may have to rely on cropping and scaling, or digital zoom, for longer focal length coverage. The patents awarded to Sony last year for lens designs employing curved sensors certainly seem to indicate an emphasis on prime lenses, although one zoom lens design with curved sensor does exist (for a 1"-type sensor).

Digital zoom or not, we'd be excited to see a small, compact RX1 replacement with an even simpler lens design that provides great edge-to-edge, corner-to-corner performance. Wouldn't you?

Read our original story below...

Speaking at the VLSI symposium in Hawaii, Sony device manager Kazuichiro Itonaga showed a curved full-frame sensor and a smaller, curved 11mm diagonal sensor (which would be classed as 2/3"-type). The former is suited well for a fixed-lens full-frame camera (such as the RX1), while the latter is sized similarly to sensors in enthusiast compacts as well as the Nokia Lumia 1020. He did not detail the process but it appears they are fabricated flat, bent into shape using a custom machine, and then backed with ceramic to maintain the bent shape permanently.

But why a curved sensor? In a nutshell, a curved sensor is designed to combat the field curvature (also known as Petzval field curvature) associated with simple lenses imaging a flat plane on a flat imaging sensor. Field curvature results from the fact that the effective focal length light rays experience decreases the more off-axis light rays are from the lens' optical axis (the optical axis is defined by a line running from infinity through the center of the lens). In other words, the more off-axis a light ray is, the further in front of the focal plane (defined by focused on-axis rays) it falls. In fact, as you can see in the image below, a flat plane in the real world is imaged on a curved surface known as the 'Petzval surface', not a flat surface (labeled 'Theoretical image plane' below).

Because of field curvature of simple lenses, a flat plane in the real world is imaged on a curved surface known as the 'Petzval surface'. Image sensors tend to be flat, therefore requiring corrections for this field curvature. [Source: astrosurf.com]

Lens manufacturers go to great lengths to combat field curvature by introducing field flattening elements - necessarily making lens designs quite complex. Furthermore, these elements often introduce other aberrations; for example, there's a well known tradeoff between astigmatism and field curvature.

What if we could work with the field curvature inherent in lenses, as opposed to against it? That's exactly where curved sensor technology can help. Curved sensors allow simpler lens design, since light rays entering the lens from oblique angles don't have to be corrected to project onto a flat surface. They also combat peripheral light fall-off by improving light collection at the edges of the sensor, since the light enters the photosites at a less oblique angle (back in the days of film, this sort of fall-off was somewhat mitigated due to the fact that film dyes were more accepting of oblique light rays than deep pixel wells are). In fact, a 2x increase in photon collection efficiency is reported for the periphery, with a 1.4x increase in sensitivity in the center of the sensor as well. The latter may be due to a better ability to collect oblique light rays entering the peripheries of the lens. All of this means that there's a potential for the use of faster, brighter, simpler lenses without the significant peripheral sharpness and light fall-off we've become accustomed to.

Sony also found that the bending process improves the sensor's fundamental performance. The strain introduced into the sensor upon bending widened the energy band gap and decreased dark current (residual electronic signal present in the absence of any external light). Both of these achievements should contribute to increased image quality.

You may have noticed that the bottom panel in the figure above resembles a human eye. Indeed, a curved sensor can also be thought of as a form of biomimicry. Itonaga himself stated that the level of curvature achieved in Sony's new sensor is similar to that found in the human eye. The human eye has a relatively simple lens and a curved photosensitive surface known as the retina (the analog of a camera sensor). This allows our eyes to image flat planes in the real world with higher acuity than if our retinas had been flat, by - to a degree - avoiding the field curvature explained above.

While the team from Sony showed off images from the curved sensors integrated with lenses, it did not provide comparisons with equivalent systems employing traditional, flat image sensors. One caveat we feel compelled to point out is that an image sensor with a given amount of curvature must be matched to a particular lens such that the curvature matches the inherent field curvature of that lens (which changes with focal length, aperture, etc.). This means that such curved sensors will probably only find their ways into fixed-lens cameras in the near future. That is, until a point in time when the curvature of the sensors can be adjusted on the fly (if ever).

That said, the potential for simpler lenses in such fixed-lens cameras is quite compelling. It's interesting to note that last year Sony was awarded a patent for a number of lens designs, including a rather simple 35mm f/1.8 lens with 4 elements in 3 groups, shown below.

In 2013, Sony was awarded a patent for a number of lens designs, including the rather simple 35mm f/1.8 lens paired with a curved image sensor shown above. [Source: Egami]

We note that while the idea of the curved sensor itself isn't new - the image sensor array at the Kepler space observatory is curved to match the field curvature of the telescope, and John A Roger's group at the University of Illinois showed a prototype hemispherical electronic eye camera back in 2008 - Sony is the first to show working curved image sensors of these sizes integrated in an imaging system. More importantly, it seems that the technology from Sony is not just technology in development, but in fact appears to be almost ready for production. According to Image Sensors World, Itonaga has stated: "The team has made somewhere in the vicinity of 100 full-size sensors with their bending machine. We are ready."

Comments

the curvature of these new sensors must be such that its radius should have the vertex exactly on the "nodal point". In such a way that each pixel is equidistant from the nodal point. In this way the focus works much like human eye and all the physical problems (aberration, vignetting, focus at the edges) arising from the progressive increased distance of the pixels of the sensor flat (as like the points of the film) moving from the center toward the edges, are eliminated in one fell swoop!But there is a problem:the nodal point is not a fixed point. It moves by changing the focal length of the lens. So I wonder, what consequences it will result.Either manufacturers build the perfect camera lens with "fixed focal length", or they invent variable curvature sensors? I really do not know

This will bring some significant movement into more than one segment:- thinner & lighter cameras to ultra thin mobile devices at usual sensor sise- bigger sensors to camera units of common mobile devices- slimmer bodies of enthusiast cameras with fixed non-zoom lenses

Sony is the biggest player in conventional design sensors. It seems to be a good idea to secure the domination by exploring technologies that provide benefits in thinner desings. The marketting battle of mobile devices loves to claim a device as thinnest alongside with best photo quality - the camera units have to become thinner. And we are making huge steps towards wearables...

This will provide for better sharpness and contrast in the corners, closer to what you are getting in the center of the image.

It will, however, require an entirely new line of lenses. Use lenses with elements designed to correct for the flat surface on the other side, where distance varies instead of being constant, and you would have the inverse problem.

So do not expect a new line of cameras to be made to be backwards compatible with any lenses out there. But that's OK. There are people changing systems all the time, especially in this day and age.

Just had a thought: To read a curved focal surface with a flat sensor...

If the image was "scanned" by the sensor-read process in a circular fashion as the sensor moved towards the lens during the shot.... This would be easy with a liquid-crystal shutter near the focal "plane"The process starting at the centre as a circle and then becoming an anulus as it radiated to the corners, we should have compensated for our curved field.

The camera could be equipped with the curve parameters of any lens. The sensor moving by piezo or moving-coil actuation may be a limit to higher shutter speeds.

Simpler - curved focal-surface - lenses enabled by curve on the sensor? Cheaper lenses for novelty-fun photos maybe. However with the advent of in-camera processing able to compensate for barrel, pincushion and chromatic aberation, AND the ability to make non-spherical lenses, this seems a bad move. Swallowing a spider to catch a fly. Sure our eyes are spherical but the brain enables us to see the side of a house as a rectangle. The curved sensor, only appropriate for a given lens, limits interchangeability. It looks like a strategy for cheapness. A rush to the bottom. Pezval's lens was fast but unsharp and passed into history - so should this

I'm always impressed with the number of negative comments when any Sony new tech is presented. I believe if it were Nikon or Canon those same "experts" would praise the idea! IMHO it's time for people to start accepting the fact that Sony is here to stay, already having over 50% of the entire imaging sensor market and growing. Sony cameras are becoming the top in advanced technology and performance, being them fixed lens or system ( interchangeable lens ), mirrorless or not. I understand the system cameras users who, over the years, have spent a ton of money in their Canons/Nikons/... bodies, lenses, accessories, etc, having a hard time in even thinking of changing. Nevertheless, technology keeps relentless and inexorably advancing and Sony seems to be now really running that show and the one to be looked at, either to partner ( as in the image sensors case ) or to fight...!

As interesting as this sounds (especially to those of the recent digital age, and some Sony engineers apparently) this is just OLD technology/concept revisited...We tried this back in the film days (in concept) for the very same reasons - smaller/simpler/cheaper lenses with better performance across the image frame, etc..What was determined back then (as is being 'discovered' today) is the very limited beneficial uses provided. Wide angle lenses, due the intrinsic field curvature of the elements used in their design, are almost the only area of benefit. Just about anything longer than ~50mm would itself have to be -redesigned- in order to project effectively, which would of course exponentially consume any cost savings of simpler/cheaper wide angle lenses.Sony has provided theoretical information to suggest greater sensor performance, noting signal noise reduction etc, but nothing that could not be accomplished by putting R&D towards 'fewer' 'larger' and 'better' photosites..

@Cheng - You may have misinterpreted 'in concept'.This has already been done by many people, and its failing was not due to technical limitations. It was that no tangible benefits were provided at an industry level due to the limitations of application = the diversity of existing equipment.It was rapidly discovered that the curvature beneficial for any particular lens was 'lens specific' so the modifications made only benefited the lens used at the time - change lenses and you had to modify again.The situation is even worse today as the industry would need the likes of Canon, Nikon, Leica, Zeiss, Sigma etc to redesign their entire range of lenses to meet a standardized field curvature just to use a Sony sensor..? Not going to happen.For companies like Sony (who barely make lenses) there may be a market for fixed focal length pocket cameras, but in those types of cameras the lens can be designed to work with existing sensors much cheaper than redesigning a sensor and lens together.

Yes, the olden days are important, but optical design technology has come a long way since then. No one has to spend weeks drawing ray tracings so perhaps engineers will be able to overcome the limitations that torpedoed this idea the first time around. I would pay a lot to be able to switch from 3 lb, 15-element lenses to something much lighter and simpler.

@Reality Check: there is an increasingly market for large sensor, small compact photographic devices. You know, the ones you really take to the streets everyday. Sony doesn't need companies to design lenses, they already know where the money is at. If they have sold many RX1 and RX100, they know there is a market for such cameras.

And if we take this to mobiles...Iphones are using Sony sensors for a while, and if they are selling millions of those devices, imagine many large sensor fast lenses designs without proturding cases.

Now, your main concern is interchangeables devices. Well, as you said, the market isn't going to change the current standard (flat sensors) for this tech. But remember, the current market is shrinking.

Good lenses are expensive and we own multiple lenses. So maybe overall it would be cheaper to have two (selectable) sensors in the camera, each having different curvature. More realistic - have one sensor in the camera, and put a sensor in the lenses which are at the extremes (either long or short lenses - I'm not sure which would make the most sense).

I agree on TVs. My dad worked on early rear projection TV's for Sylvania (we had a large one at home way back in 1980!). When they left town, he brought home a competitor's (I think Panasonic) curved screen (front projected, like an outdoor movie). It was not good off-center - of course! But cameras ARE "in center" - the imager is the "audience". I really don't see how they get around the fact that different lenses would require different curvature. Maybe a curved sensor lessens the complexity of lenses, but it does not get rid of the issue of the lens and sensor curvature differing.

If you're showing off a great new feature, wouldn't it be nice to, you know, actually show it off?

On a more serious note - why add a whole new stage in sensor manufacturing (read: very expensive), just to make the corners slightly sharper? *And*, like the article mentions, to produce sensors unsuitable for zooms and for interchangeable lens cameras?

Makes no sense to me.

Unless, like others mentioned earlier (http://www.dpreview.com/articles/2279255612/sony-s-curved-sensors-may-allow-for-simpler-lenses-and-better-images?comment=0577067993), there's a disconnect between marketing and engineering, and the real benefits have nothing to do with the curvature of the focal plane and everything to do with mechanically stressing the silicone (which enhances the sensor's performance - meaning you get less noise and more DR).

Likely, in final production the sensors won't actually be curved, just stressed.

It's not just for sharper corners. It's to maintain corner sharpness - or make them sharper - while decreasing the complexity & size of lenses. And seeing as how Sony appears to be obsessed with maximizing sensor size to overall size/weight ratio...

For example, imagine a RX1(R) with an even more pocketable - yet still just as bright, or brighter - lens.

Sorry, this still doesn't sound convincing. Improved corner sharpness (at some apertures, at some distance settings) just does not sound important enough to warrant a separate *type* of sensor, only suitable for fixed-focal-distance, non-interchangeable lenses.

The benefits are not that huge - a slightly simpler and smaller lens (it would still need to correct for things like coma, astigmatism, geometric distortions, etc.)

The drawbacks are enormous - no zoom, no interchangeable lenses. A sensor that only works for a single type of camera. This means low sales volume, coupled with a separate manufacturing process. This, in turn, increases the cost significantly.

While RX1(R) are very nice, they are already quite expensive. An RX1 with a bent sensor would easily cost twice as much, probably more.

But since you brought it up, it's worth mentioning that getting rid of the need to correct field curvature can simplify astigmatism correction. Because right now there's a delicate balance between astigmatism and field curvature - often the correction of field curvature makes it difficult to completely correct for astigmatism.

Put another way, without the requirement to flatten the Petzval surface, it's easier to simply get the Sagittal and Tangential planes to coincide on the Petzval surface than to flatten both S & T planes. See figures 2 and 3 here.

"get the Sagittal and Tangential planes to coincide on the Petzval surface" - if I understand this correctly, a comparatively simple symmetrical lens system can correct for astigmatism, while still having a curved image plane (see p.42 here):http://www.iap.uni-jena.de/iapmedia/de/Lecture/Imaging+and+aberration+theory1396134000/IAT13_Imaging+and+aberration+Theory+Lecture+8+Astigmatism+and+field+curvature.pdf

Still, that's a highly specialized solution. Aside from ruling out zooms and interchangeable lenses, I suspect ultrawide and macro lenses would be tough, too. And probably not pancakes either (at least not ones that, like RX100(3), rely on exotic aspherical elements).

So we come back to marketing - such cameras would have a limited market, would require a separate stage in manufacturing process, and be very, very expensive.

On the other hand, what if mechanically stressing a sensor gives as much benefit as, say, Sony's own BSI? *That* would be headline news.

"get the Sagittal and Tangential planes to coincide on the Petzval surface" - if I understand this correctly, a comparatively simple symmetrical lens system can correct for astigmatism, while still having a curved image plane

Yes, exactly.

And, yes, sensitivity benefits are icing on the cake. Or maybe correction of field curvature is icing on the cake. All a matter of perspective & what you care about :)

Aside from what I care about (which very definitely isn't a $10,000+ camera with a fixed-everything normal lens), there's a matter of feasibility.

Commercially, a specialized sensor that could only work in cameras with non-interchangeable/non-zooming/non-WA/non-macro lenses, just wouldn't sell.

Now that I think about it, $10,000 estimate is probably on the low end. The lens-type limitation would reduce the number of sales, which would makes it even *more* expensive, which would reduce the number of sales even further, and so on.

On the other hand, a new sensor technology that would deliver an extra stop of light sensitivity to *all* cameras, would fly off the shelves. Just like BSI does.

I see people making reference to the sensor mimicking the human eyeball. However, the sensor, as shown, is concave. Wouldn't it have to be convex to mimic an eyeball? Maybe we need a convex sensor and a fresnel lens? But then there'd likely be a decrease in image quality...

On another tangent, why would the lens need to be round? Can you make, say, a 3x2 rectangular flat lens to convey maximum light to a 3:2 sensor? Seems you could significantly reduce overall camera (lens) size by doing so...

What's next is sensors that flex with the changing focal-length of the lens. Perhaps the sensors will be built right into the structure and mechanism of the lens, for maximum compatibility at all focal-lengths. This could lead to the capability for a photographer to change sensors in a camera, along with the lenses.

How about dual sensors ... one stacked in front of the other. As the focal length cross thresholds, the sensors swap positions by shuffling ... marketing could make real hay with something that inherently ridiculous :-)

IMHO it will work well only when the sensor is created curved. Here they are making them and then bending them. Just hope they bother to do it properly!!

Then we can look forward to the kind of modular machine others like Ricoh have already sold us with the lens and sensor as a single sealed unit. What a money spinner!!!

With the hiked prices Sony are already charging for their not so very good E mount primes (already double the cost of a canon or nikon APS-C prime) doubling again in cost with an attached sensor to slot into a redesigned body- sold at a premium price because you wont need to change it, will we buy them? Yes, of course, we really are that stupid!!

Lenses have always been the area of the camera market where consumers have a wide choice to chose from , especially when you consider the second hand market. People could quite easily buy a new body and use their existing collection of lenses.

This is a fantastic way for manufacturers to make the entire second hand lens market obsolete. If this makes it to production in the future we will all need to buy lenses to match our curvy sensor bodies. They may be touting it a an advance in technology, but it screams of a new way to make people buy more kit.

I don't think the market [paying customers] will allow for generations of camera bodies and lenses to become obsolete over night, let alone over an extended period of time. Who is going to toss out their entire inventory of equipment and jump to this 'system'. This 'system' may have some promise for a future niche market to evolve. . .

Good point and fair comment, I could definitely see this creeping into the fixed lens compact market, where lens and camera are always sold together. If it really is an advancement in technology and improves image quality, these these niche markets (as you say) would be a good testing ground.

I'm surprised to see they made curved big sensors. I'd think that especially cellphone cameras would benefit from simpler lens design and higher sensitbility. And cellphones use fixed lens-sensor units anyway. For me it would be the logical way to beginn small to use the experiences you make in the next step, which would be bigger sensores. Sony is doing the second step first, from my point of view.

This is just a technological demonstration and technology testing. Once they can do large sensors, they are capable of making small ones. Plus maybe they just don't want to reveal their smartphone cam strategy...

Next iteration will be dynamic curved sensor ("DCS"), a sensor that can control its curviness in real time. And then aspherical DCS. Aspherical DCS + liquid lens.. wow, geeky photographer's wet dream. What a wonderful future. Assuming that the machines don't take over the world and kill us all.

Yes this is an interesting point. OTOH, for a 3:2 sensor, the horizontal axis has further off-axis pixels than the vertical one. So correcting for it is arguably more important than correcting for the vertical one.

It works just like a human eye. Not very good for photography. Even this quote "A curved sensor mimics the retina of a human eye" is incorrect. The human eye, only has sharp focus at the center of the retina.

Perhaps a way around the problem of desiging specific lenses for specific curvetures would be to place the sensor on a platform that can move precisely back and forth within the camera based on information sent to the firmware by the Sony lens that has been mounted. Would beat designing a lens/sensor combo for every focal length I'm thinking.

It has been known for years that a simple lens images in a plane which is hemispherical. The optical trick in lens design has been to correct for this so-called distortion so that the image looks natural on a planar surface.

Some film cameras tried to overcome this problem with curved film gates, the bakelite Kodak Brownie 127 at the cheap end of the market and the Minox sub-miniatures at the other, being two examples that I know of.

So there is nothing magical in the effect Sony is describing, but its implementation will be. And if it does free lens designers to come up with superior imaging optics, then Sony should be applauded, not attacked.

Whilst I accept that in pure geometry, a plane is flat, and thus my comment may at first seem to be a non-sequitur, I was using it in the world of imaging and where there is often reference to a "flexible and curved focal plane".

Also I couldn't bring to mind a single word to describe what I wished to portray as a projection drawn on the inside of a section of a hemisphere, and which is, of course, more than a simple curve in one axis only.

@ BadScience.

Yes, you did read my mind as to what I wished to portray, and which I've expanded upon in my reply to JackM above.

And as an extra benefit the process actually improves the performance of the sensor. I believe that the article states that the dark current is reduced just from stressing the crystal. This bodes well for even more sensitive sensors as well.

Thats a problem of sony. The good idea is not enough... the whole system counts. They build the best sensors but f.e. have a lousy system around their A7-bodies with 4 different lenses.

A camera is not the body, only. You need optics, flashes, software or accessoires. This is fine for a fixed lense full frame cam... yepp.But I hope the curved sensor is not to expensive to build. At least not more that the 2 or 3 Glasses you get rid off in the optics...

c'mon, a7 series camera have been around for months only. We are supposed to have 15 lenses by end of 2015...and having 5 lenses available (not 4) with two more lenses announced right now is a good sign.

Well, it took me some time, but my memory finally tied together various strings and I figured out why the bending stress is reported to reduce noise: When a chip is bent, the electrons in the molecules which are in the area of stress are literally moved out of thier electron hole (this is scientifically accepted), leaving that place available to resist "dark current."

While curved sensor will definitely help to get well performing optical designs that are simpler and therefore cheaper, there will be a problem left - all lenses that will be designed for such a camera will have to have the image plane curved in the same way. AND gone is using older or 3rd party lens on such a camera if the camera has curved sensor, but the XY lens.

Still this may be very interesting for fixed lens camera (again - the image curvature will need to stay constant over the zoom range)

What if they also release an adapter that can be placed between camera and lens that is "negative" in effect so that old lenses could be used?Unsure how that would work because it sounds like it should add up to the length between lens and sensor (additional adapter between)?!

Here's a thought... maybe one day sensors can be built using 3D printing technology bringing down the cost so that you get a perfectly matched curved sensor built into a prime lens. Dust proof and weather resistant. Three lenses and a body and you are good to go. Never say never.

So far the discussion has been purely qualitative. We know only that the field curvature will depend on the lens design, FL and aperture. So, is it possible to create a not-too-expensive family of lenses (including zooms) with roughly constant FC? If that is not feasible and the FC in the family would range, say, from 1 to 9 arbitrary units, how much improvement we would see with the optimized (5 units) sensor compared to the flat one?

Kodak brought out a set of curved field lenses for their slide projectors back in the 1970's when their testing revealed that cardboard mounted Kodachromes all bowed identically in their card board mounts. Up till then you had to remove the cardboard mounts and remount the positive in thin glass plates if you wanted a sharply projected image.

Yes, as mentioned, having a curved sensor will simplify lens design in general. Lenses can be designed for a specific curve and still have a lot of imaging advantages even if the ideal solution would be a different curve for each lens. (I guess someday a curved sensor could be built into each lens on an interchangeable camera as Ricoh did.)

Btw my guess is these are concave sensors not a curve in one direction on an otherwise flat sensor. But I'm not sure.

This is Sony, I seriously doubt that they will dedicate this new design to just fixed-lens point and shoots only. Think about the benefits to having a curved censor on a video camera, this is where the new design will truly shine.

I have to say all kudos to Sony here, but I have a feeling the initial offerings will be a compromise. Imagine a fixed lens camera/camcorder, with its 20x zoom, the required curvature on the sensor would surely be different at different focal lengths? So Sony will make the sensor curved at some optimum? I imagine that will still simplify the lens construction. You can be certain Sony is right now developing a sensor with variable curvature. You really have to hand it to the Japanese for their technology.

Nah, they will offer a big sensor on a small package with a bright lens with a fixed focal lenght. Doubt they will offer a zoom as first product with such a sensor, so no compromises at all. Just like the RX1.

It is truly innovation that Sony have achieved, however, there are still a lot of obstacles in front of it. Lens/sensor matching(different curvatures of sensors will have different matching types of lenses) with AF, IQ, EV, etc. This will be a great potential new technology in photography.

Although the design simplified the lens construction, still need to know the performance of the lens/curved sensor and the target price that it first hits into the market. Lets cross our fingers, wait and see.